A system for controllling equipment within a telephone subscribers' premises using dtmf telephone tones
CA 2133950 C · Owner: Bradley, Graham C. · Inventors: Bradley, Graham C.; Stretton, Alton O.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A system for controlling telephone and non-telephone equipment located on the premises of a telephone subscriber is disclosed. The system includes at least one internal tone control device (ITCD), connected between a telephone outlet and the controlled equipment. The ITCD receives decodes and validates a sequence of, DTMF signals converts it into a d.c. control signal and monitors the respectiveequipment with the d.c. control signal which remotely switches on/off the respective equipment. A plurality of different appliances can be operated in a "non-line ofsight" mode over the telephone lines. A unique sequence of DTMF signals is associated with each ITCD. The sequence is selected such that …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 20, 1994 and granted April 13, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 20, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 20, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.